Microwave-assisted multicomponent domino cyclization-aromatization: an efficient approach for the synthesis of substituted quinolines

A solid acid-catalyzed microwave-assisted synthesis of substituted quinolines is described. The quinolines were synthesized by a multicomponent domino reaction of anilines, aldehydes and terminal aryl alkynes. The synthetic pathway involves the formation of an imine, followed by the intermolecular addition of an alkyne to the imine. This intermediate immediately undergoes ring closure and oxidative aromatization. The reaction is catalyzed by montmorillonite K-10, a strong, environmentally benign solid acid. The multicomponent approach yields the products with nearly 90% atom economy in excellent yields in a matter of minutes. The use of microwave activation reduces the reaction time significantly.